Shaping fiber articles.



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K crease ot pliability, through the agency of All WWO fi'IfiGHER, Uh STUTTGALRT, GERMANY, ASSIGNOE 'ro FIRM F ROBERT BOSCH, 0F

SHAPING: FIBER ARTICLES.

Patented Aug, t3, tfitfi,

ltfl't'fiwfifi, specification ct Letters Patent.

Ito brewing.

To all whom it may concern be it known that Ltlrro lFrsoHnr a subject of the Emperor of Germany, residing at Stuttgart, fipittastrasse 8, Germany, have invented certain new and useful improve ments in Shapin Fiber Articles; and l do herebydeclare t e following to be a full, clear, and exact description of the invention, such as will'enable others skilled in the art to which it appertains to make and use the same.

The dense brittle fibrous material now widely used in the electrical arts for urposes of insulation, particularly in the orm ct insulating tubes tor electric conducting cables, and lmown to the trade as fiber or red fiber is of such a character that,.in its ordinary commercial condition, it cannot be bent without breaking; so that when it has been desired to. use a bent tube, as is frequently the case, no method has been tnown whereby the finished tubes could be cut.

The subject-matter ot the present application is based upon the discovery thatch- 1] ects of fiber can be bent very considerably it they are first caused to swell, with inmoisture within the pores of the material; and that articles so treated will retain the bend imparted to them and take a permadtl nent set in the new shape it they are restrained by mechanical means in the new shape until the agency which has caused the material to swell has been withdrawn.

l have found that the requisite swelling and increase of pliability canbe efiected by means ot the moisture content of the ma-- heat is applied to expand the contained moisture, as by heating the unbent fiber ar ticles over a dame, care being taken that the material is not'burned. It is likewise possible to produce the desired swelling ot the material by the application of moisture without the application of heat, as by soaking the material in water, since the material is extremely hygroscopic. The method succeeds best, however, if the parts to be bent are immersed in a liquid which has been heated to the desired temperature. 7 I

After the material has been'so treated it may be bent to the desired shape, and should then be held b mechanical means in that shape until it as been cooled or dried, or

' Application filed Annually t, 1913. beriall Ito. recast;

treated, retain without change the bent shape imparted to it. 7

By this method have been able, for example, to bend without dificulty and give a permanent set to a fiber tube of one inch external diameter, the bend taking the form ot a right angle, it being understood that during the bending operation suitable precautions are taken to avoid flattening the tube at the place ot bending. vSuch a bent article maybe installed in usual places, there being no material reduction of its insulating properties.

After the conclusion of the bending operation it is possible, and even preferable, to prevent the re-absorption of moisture by impregnating the article with a moistureexcluding material such as paraffin. This may be accomplished by laying the shaped and stiflt article. in melted paraffin, which then fills the pores and 'hardens, when the article is removed from the bath and cooled.

in those cases in which the bent parts are prevented by the manner of their ultimate employment as, forinstance, by confinement in the places where they. are installed, from coming back intothe original unbent posi-. tion, the method requires no further enlargement. iln many cases, however, as when a fiber tube is used to protect electric conducting cables which are to be freely suspended, the treated and bent objects must be protected against the reabsorption of moisture from the air, since otherwise they would soon return to their original unbent adage and, moreover, they are not always su ciently insulating after undergoing the described treatment. For this purpose the bent objects may be provided with a coating of lacquer or other moisture-excluding ma terial, and as long as the coating of lacquer remains in good condition the bent object will retain the shape imparted to it.

The bending and protecting steps in the process hereinbefore described may, with advantage, be efiected simultaneously by immersing the material in a heated bath of melted parafiin or other moisture-repelling material until it has acquired the requisite swelling and increase of pliability, then bending the article and securing itin the bent shape, and then allowing the absorbed paraflin to cool and solidify so as to fill the pores and prevent subsequent absorption of moisture.

Having thus described my invention what I claim is:

1. The method of treating tubes composed of dense brittle fibrous insulating material such as that known as fiber to shape them, which consists in immersing a portion of the tube in a heated bath of a waxy-material 'such as paraflin to soften it and make the material of the tube pliable then bending the tube to the desired shape while it is in the softened pliable conditionand while impregnated with the material of the bath, and maintaining the tube in'the new shape until, as a result of drying and cooling, it stifl'ens and sets with the pores thereof containing the material of the bath in a hardened form; substantially as described.

2. The method of treating articles composed of dense brittle fibrous insulating material commercially known as fiber to shape them. and to cause them to retain the new shape, which consists in'causing them to swell with an increase of pliability by immersion in a heated bath, bending the swelled and pliable article to the desired shape, maintaining it in that shape while withdrawing the softening agency until the article stiifens and sets in the new shape, and applying a water-proofing material to the article to prevent the subsequent absorption of" moisture thereby; substantially as described.

3. The method of treating articles made of fibrous insulating material which is dense. and brittle when hard and which is commercially known as fiber, which consists in making a rigid article from the material, causing the article to swell and become pliable by immersion in a heated bath,

bending the swelled and pliable article to the desired shape, maintaining it in that shape while withdrawing the softening agency until the article stifiens and sets in the new shape and applying a waterproofing material to the article to prevent subsequent absorption of moisture thereby; substantially as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

OTTO FISCHER. Witnesses:

PAUL WOLFOBT, HERMANN SCHNEIDER. 

